SWEAT GLANDS

From Big Medical Encyclopedia

SWEAT GLANDS [glandulae sudoriferae (PNA, JNA, BNA)] — the glands of skin which are developing and emitting sweat. Item. participate in thermal control and cause specific (specific and individual) began to smell bodies.

Fig. 1. The diagrammatic representation of cross section of skin with a hair, ekkrinny and apocrine sweat glands: 1 — epidermis, 2 — a hair, 3 — a stalemate time of an ekkrinny sweat gland, 4 — a lot channel of an ekkrinny sweat gland, 5 — a derma, 6 — the tail of an ekkrinny sweat gland, 7 — hypodermic cellulose, 8 — the tail of an apocrine sweat gland, 9 — a lot channel of an apocrine sweat gland, 10 — the place of falling of a stalemate channel of an apocrine sweat gland into a funnel of a follicle of a hair.
Fig. 2. Microdrug of skin of axillary area: 1 — epidermis, 2 — a derma, 3 — hypodermic cellulose, 4 — the tail of an ekkrinny sweat gland, 5 — the tail of an apocrine sweat gland, 6 — a hair, 7 — a stalemate channel; coloring hematoxylin-eosine; x 100.

They represent simple tubular glands with the tails curtailed into balls. Everyone Item. consists of the tail (pars terminalis), or a body, and a stalemate channel (ductus sudoriferus) opening outside a stalemate time (porus sudoriferus). Existence of a time on skin for the first time was found in 1687 by M. Malpigi. It is considered that the Item. were opened in 1833 for Ya. Purkinye, however in 1662 Mr. N. Ste-non described the small hypodermic glands connected with skin the thinnest channels. On character secretions (see) the Item. divide on ekkrin-ny (merocrine) and apocrine (see. Glands ), differing on development, morfol, to signs and functional value (fig. 1 and 2).

Ekkrinny, or small, Item. are available in skin almost everywhere, except for a red border of lips of a mouth, a head and an inner surface of a prepuce of a penis, a clitoris and small vulvar lips; their total quantity makes 2 — 5 million. Most of all glands are on palms and soles (St. 400 by 1 cm 2 ) and in skin of a forehead (apprx. 300 by 1 cm 2 ), then go in decreasing order: on an upper extremity — a back of the hand, a forearm and a shoulder; on the lower extremity — the back of foot, a shin and a hip. On extensor surfaces of extremities of the Item. it is less, than on flexion, is one trunk less, than on upper extremities and the head. Children have density of the Item. because of the smaller surface of skin is several times higher, than at adults. Volume of one ekkrinny Item. at the newborn it is equal to 0,0026 — 0,0046 mm 3 , at adult 0,012 — 0,018 mm 3 . Bulk volume of all Items. at the adult makes 34 cm 3 , general surface of a secretory epithelium of 5 m 2 , the area of all stalemate time is 94 cm 2 .

Apocrine, or big, Item. crotches, especially around an anus are localized in skin of axillary area, area of a pubis and the part of a stomach adjoining to it, skin of a scrotum, big vulvar lips (gll. circumanales), and in a peripapillary circle of a mammary gland (gll. areolares, montgomerova of gland). Modified apocrine glands are the ciliary (mollevsky) glands located in centuries at eyelashes; the predoor glands of a nose and gland of outside acoustical pass allocating an earwax. The greatest development is reached by axillary apocrine Items., forming together with ekkrin-ny Items. reddish macroscopic ferruterous weight, so-called axillary body. Women have these glands, as well as other apocrine Items., are developed stronger, than at men; they change the volume according to phases of a menstrual cycle.

Comparative anatomy and ontogenesis

Ekkrinny Items. phylogenetic younger. At primacies they are located almost only on soles and fingers and develop the watery secret facilitating coupling by a foot with the soil and capture of objects. At anthropoids and the person ekkrinny glands spread on all body surface and play a significant role in thermal controls (see). Apocrine Items. have more ancient origin and are eurysynusic among mammals. Distinguish two types of such glands; the thermoregulatory glands of hoofed animals and scent glands functioning at different types of animals in a breeding season and playing a role in sexual behavior. The person has apocrine Items. remained only in nek-ry sites of an integument, they cause a specific smell of a body, in the development are always connected with hair.

Fig. 3. Microdrug of skin of a sole of a fruit of 18 weeks (rudiments of ekkrinny sweat glands): 1 — epidermis, 2 — stalemate channels, 3 — tails of sweat glands; coloring hematoxylin-eosine; x 100.

Formation of the Item. begins with the 3rd month of pre-natal development when on palms a bit later on soles rudiments of ekkrinny Items appear. in the form of the breeding cellular groups of epidermis. For 4 months the tyazh of an epithelium plunging into a derma are formed. In other parts of a body rudiments of the Item. appear on the 5th month. On the 6th month they reach a hypodermic basis (cellulose) and balls (fig. 3) begin to be formed. Gleams in tails of ekkrinny Items. appear on the 7th month; the sewerage of stalemate channels and opening of a stalemate time occur at the end of the period of pre-natal development. Ekkrinny Items. begin to function, according to one researchers, at newborns, according to others — at the end of the 3rd or the beginning of the 4th week after the birth. These glands reach full development only to 5 — to 7-year age. Apocrine Items. develop from an epithelium of follicles of hair, at newborns their tails and canals are deprived of a gleam. These glands begin to function only from the beginning of puberty, reach full development with approach of puberty, and at senile age their most part is reduced. New Items. in the post-natal period are not formed.

Histology

Tails of ekkrinny Items. are put in a derma or hypodermic cellulose. Ferruterous tubules consist of internal and outside layers. The inner layer is presented by one layer of secretory cells (glandulotsit) lying on a basal membrane. The periblast is formed by myoepitheliocytes. Glandulotsita, depending on a phase of secretion, have the cubic or cylindrical form. In tails come to light inside - and intercellular secretory tubules. Cytoplasm of glandulotsit contains drops of fat, a granule of a pigment and a glycogen. Potovy Canal goes at right angle to the surface of skin, in epidermis it has the shtoporoobrazny course. The wall of a stalemate channel consists of two layers of epithelial cells. Histochemical and ultrastructural features of the cells covering stalemate channels (existence in them of a glycogen, RNA, microvillis and numerous vesicles) indicate their metabolic activity and participation in absorption of substances from a secret of tails of the Item.

Tails of apocrine Items. are localized in a derma or in hypodermic cellulose. Their ferruterous tubules have wider gleam, than ferruterous tubules of ekkrinny glands. They can branch and form side outgrowths. Glandulotsita do not contain a glycogen, in their cytoplasm there are RNA, numerous drops of fat and a granule of polysaccharides. At histochemical and electronic microscopic examination distinctions between glandulotsita of separate groups of apocrine Items come to light. Potovy channels of apocrine glands open in funnels of follicles of hair over channels of sebaceous glands, but sometimes their mouths for the second time are displaced on the free surface of skin. The wall of a stalemate channel has the same structure, as at ekkrinny glands. The secret of apocrine glands more viscous, than ekkrinny, has alkali reaction and is thrown out in the separate portions. Secretion of these glands is connected with function of gonads.

Blood supply of sweat glands is carried out by arteries of hypodermic cellulose. Near the tail of gland the afferent artery is divided into branches, one of to-rykh goes to a stalemate channel, and others form dense network of capillaries around the tail of the Item. Outflow of blood happens on the venules lying between curls of the tail in the vein forming at the beginning of a stalemate channel. Average and peripheral departments of a stalemate channel are supplied with blood from subpapillary arterial network of skin.

Innervation of ekkrinny Items. it is carried out by fibers of a sympathetic nervous system. Apocrine Items. are deprived of secretory nerves, their function is regulated by hormones of marrow of adrenal glands.

Physiology Item. — see. Sweating .

Pathology

Pathology of the Item. includes: malformations, functional disturbances, dystrophic changes, inflammatory defeats, and also tumors.

Malformations include inborn lack of the Item., an ectopia on sites of mucous membranes — Fordyce's disease, cystous and dystrophic changes of inborn character. Many scientists carry the syringoma which is shown in the form of small multiple flat translucent small knots on skin of a neck, a breast, a century to malformations of stalemate channels.

Functional disturbances of activity of the Item. happen fiziol, and patol, character. E.g., fiziol, strengthening of sweating — hyperhidrosis (see) — is defense reaction of an organism during the overheating, physical tension, etc. Functional disturbances of activity of the Item. patol, character are connected with functional and organic changes central and the autonomic nervous system, cardiovascular system, disturbances of a water salt metabolism, function of kidneys, etc. Thus the hyperhidrosis without essential changes of chemical composition of sweat (a hyperthyroidism, a climacteric) is more often observed. At children, especially chest and early children's age, the diffusion hyperhidrosis can be display of rickets, tuberculosis and other diseases. The localized hyperhidrosis (palms and soles, large skin folds, etc.) is more often caused by a neurangiosis, endocrinopathies. At a hyperhidrosis on skin there can be small translucent intraepidermalny bubbles (see. Dyshydrosis ). In some cases the hyperhidrosis is followed by disturbance of chemical structure sweat (see) which can get an unpleasant fetid smell (see. Osmidrosis ). At uraemia and an azotemia urea comes to sweat in a significant amount that can be followed by its crystallization on skin (see. Urhydrosis ). Dysfunction of apocrine Items., expressed in a delay of sweat, it is observed more often at female persons during puberty and can be followed by formation of small pruritic small knots in axillary poles, in nipples of mammary glands and an anus (see. Fox — Fordyce a disease ). Decrease in functional activity of the Item. up to complete cessation of products of sweat — an anhidrosis — it can be observed at avitaminosis, an addisonovy disease, a leprosy, cirrhosis, nek-ry poisonings and intoxications (see. Anhidrosis ).

Dystrophic changes of the Item. the acquired character arise at senile age and at a number of diseases — sclerodermas, atrophies of skin, etc. However quite often dystrophic changes of the Item. are connected with the hereditary features of their morphology and functional activity which are shown in reduction of quantity of bookmarks of the Item. per acre skin, thinning of the epithelium covering stalemate channels of glands, and a secretory epithelium of tails, decrease in secretory function and education in stalemate channels of horn traffic jams with development of stalemate cysts. Hereditary dystrophic changes of the Item. are observed at Verner's syndromes, Thomson, an ichthyosis, a violent egshdermoliz, etc., the full atrophy of the Item is possible. inborn character, caused by lack of a differentiation of structures of glands of skin, including and stalemate (see. Angidrotichesky syndromes ).

Inflammatory defeats of the Item. are most widespread. Bad care of skin, especially at children of chest age and the weakened patients, leading to disturbance of sweating is their reason (see. Heat rash ). Inflammatory infiltrate at the same time is located around stalemate channels in epidermis and a papillary layer of a derma; in hard cases (at a red heat rash) the so-called thermogene anhidrosis, ruptures of stalemate channels in epidermis is possible. Pyogenic bacteria, being implemented into stalemate canals, cause acute and hron, piokokkovy defeats of the Item. At the same time at adults hl are surprised. obr. apocrine (see. Hydradenitis ), and children have ekkrinny Items. (see. Staphylococcal infection ).

Tumors of the Item. divide on high-quality and malignant. Benign tumors meet more often. Carry to them: 1) syringadenoma (see) — a tumor in the form of a plaque with a warty surface, coming from stalemate channels and embryonal rudiments of the Item.; 2) to gidradeny — the tumor with a ferruterous differentiation and the expressed secretion of tumor cells developing from ferruterous tubules (distinguish papillary, clear cell and other kinds of a gidradenoma); 3) an ekkrinny spiradenoma (see. Spiradenoma ekkrinny ) — a tumor in the form of a single dense small knot, coming from the tail of the Item.; 4) tsilindry skin with a ferruterous differentiation (see. Tsilindroma ) — the rare tumor developing from ekkrinny and especially often apocrine Items. and their embryonal rudiments in the form of semi-spherical nodes of various sizes merging in continuous knotty growths; 5) ekkrinny to the ferry — also rare tumor connected with intra epidermal department of a stalemate channel and which is localized usually on soles in the form of dense formation of pinkish color; 6) bazaliy (adenoid), developing from the Item. and characterized by a ferruterous differentiation (see. Bazalioma ).

A malignant tumor is the rare kind of a carcinoma cutaneum — cancer of the Item. (synonym: gidradenokartsinoma, syringocarcinoma), coming from stalemate channels. The tumor can be differentiated and undifferentiated, is presented by usually solitary ulcerating node and metastasizes in internals. From apocrine Items. extramammary cancer of Pedzhet can sometimes develop. See also Skin, tumors .



Bibliography: Kalantayevskaya K. A. Morphology and physiology of skin of the person * Kiev, 1972; Materials to macro-microscopy of the autonomic nervous system and glands of mucous membranes and skin, under the editorship of R. D. Sinelnikov, page 349, M., 1948; Fundamentals of morphology and physiology of an organism of children and teenagers, under the editorship of A. A. Maher-kosyana, page 358, M., 1969; To u r about s u-m i K. Fine structure of the human sweat ducts of eccrine and apocrine types, Arch. Jrystol. jap., v. 40, p. 203, 1977; S p e a r-m a n R. J. C. The integument, Cambridge, 1973. See also bibliogr, to St. Skin .


V. S. Speransky; S. S. Kryazheva (pathology).

Яндекс.Метрика